pakistan denies the report. we will have much more on this coming up at the top of the hour. >>> the u.s. secret service is now investigating the apparent hacking of fox news' political twitter feed. after false reports said president obama had been killed. fox says it's also pushing for a detailed investigation from twitter about how it happened and how to prevent future incidents. the false tweets remained on the site for hours before they were removed. >>> proof that early cancer screenings save lives. the cdc just released a new report on one of the biggest killers in men. helps defends against occasional constipation, diarrhea, gas and bloating. with three strains of good bacteria to help balance your colon. you had me at "probiotic." [ female announcer ] phillips' colon health. >>> early detection pays off in the fight against cancer. we know that. but there's a finding in a new report about colo-rectal cancer that came out today. senior medical correspondent elizabeth cohen joining me now. what's happenin